title: Interferon gamma, interferon-gamma-induced-protein 10, and tuberculin responses of children at high risk of tuberculosis infection.
abstract: BACKGROUND
  Children in contact with adults with pulmonary tuberculosis (TB) are at risk for infection and disease progression, and chemoprophylaxis may reduce this risk. The identification of infection is based on the tuberculin skin test (TST) and interferon-gamma (INF-gamma) release assays. Other biomarkers such as interferon-gamma-induced-protein 10 (IP-10) may have potential for the diagnosis of latent TB infections.
  
  
  OBJECTIVE
  To describe IP-10 concentrations and their association to TST and INF-gamma responses in children recently exposed to adults with smear-positive TB in Brazil and Nepal.
  
  
  METHODS
  : Two surveys using the same design were undertaken to describe TST, INF-gamma, and IP-10 responses in 146 children in Nepal and 113 children in Brazil.
  
  
  RESULTS
  The concordance of TST and QuantiFERON-TB gold in-tube (QFT-IT) was high (kappa 0.73 in Brazil and 0.80 in Nepal). IP-10 responses were higher in children with both positive TST and positive QFT-IT (medians 1434 pg/mL in Brazil and 1402 pg/mL in Nepal) and lowest in children with both negative TST and negative QFT-IT (medians 206 pg/mL in Brazil and 81 pg/mL in Nepal). Children with negative TST and positive QFT-IT had higher IP-10 concentrations than children with positive TST but negative QFT-IT.
  
  
  CONCLUSIONS
  IP-10 is a potential marker to identify latent TB infections that is expressed in large quantities and with good agreement with QFT-IT. The reasons for the discrepant results observed are discussed.
authors.affiliation: Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK.
authors.forename: Roberta
authors.initials: R
authors.lastname: Petrucci
authors.forename: Nabil
authors.initials: N
authors.lastname: Abu Amer
authors.forename: Ricardo Queiroz
authors.initials: RQ
authors.lastname: Gurgel
authors.forename: Jeevan B
authors.initials: JB
authors.lastname: Sherchand
authors.forename: Luiza
authors.initials: L
authors.lastname: Doria
authors.forename: Chamala
authors.initials: C
authors.lastname: Lama
authors.forename: Pernille
authors.initials: P
authors.lastname: Ravn
authors.forename: Morten
authors.initials: M
authors.lastname: Ruhwald
authors.forename: Mohammed
authors.initials: M
authors.lastname: Yassin
authors.forename: Gregory
authors.initials: G
authors.lastname: Harper
authors.forename: Luis Eduardo
authors.initials: LE
authors.lastname: Cuevas
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000097:blood; D001938:Brazil / Q000453:epidemiology; D002353:Carrier State / Q000175:diagnosis*; D054357:Chemokine CXCL10 / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007223:Infant; D007371:Interferon-gamma / Q000032:analysis*; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology; D009390:Nepal / Q000453:epidemiology; D012306:Risk; D012680:Sensitivity and Specificity; D014374:Tuberculin Test / Q000379:methods*; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology / Q000635:transmission
chemical_list: D015415:Biomarkers; C114753:CXCL10 protein, human; D054357:Chemokine CXCL10; D007371:Interferon-gamma